Multi-stack Anodic Bonding Using Two Electrodes and Its Application in Sealing Alkali Metal

Multi-stack anodic bonding using two electrodes is realized in this paper. The process includes two bonding steps separated by one electrodes reversal. When pre-cleaned substrates of silicon and glass are piled up and heated to predetermined temperature, voltage applied between the top and bottom substrates for bonding the first interface, when this bonding process is finished, the substrates are annealed for few minutes, then electrodes are reversed for bonding another interface. This anodic bonding process provides an efficient way for anodic bonding multi-stacks substrates of silicon and glass piled up alternately, enhances the feasibility of operation and decreases the requirement of relevant apparatus for doing so. Tensile strength testing shows that this bonding method can obtain high quality permanent bonding. Furthermore, this bonding method provides a simple way for bonding silicon- glass stacks for some special use such as sealing alkali metal into cell of glass-silicon-glass structure, in which process the electrodes are directly linked to two glasses. And using this method we successfully sealing alkali metal into the anodic bonded cell.